Petunia Dursley could be a powerful witch

[wkduke51]

No: HPFGUIDX 75166

This is my first and perhaps last post. My apologies if previously 
discussed. What if Petunia (and maybe Vernon) is a powerful magical 
person, but her magic identity is a secret protected by a fidelis 
charm so it cannot be detected unless the secret keeper reveals it? 
All that stuff about Harry being protected by connection with his 
mother's "blood" family rings hollow. The physical description of the 
horse faced Petunia also doesn't jibe with the description of Lily 
Potter. For all we know that missing day in the first book was spent 
creating the refuge and cover story at No. 4 Privet. Since Dumbledore 
was the only person to know the prophesy, perhaps he has placed Harry 
in the boot camp of hard knocks to toughen him for the final duel. 
Just speculation.